258 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 12 



KEY TO SPECIES 

 1 . Plants small 2 



1. Plants several centimeters tall C. soccoriense 



2. Axis not reaching 100 jt* diam 3 



2. Axis below exceeding 100 /A diam 4 



3. Branching radial C. epiphyticum 



3. Branching bilateral C. rupicolum 



4. Cells of the branchlets seldom more than two diameters long, 



the end cells not aculeate C. pacificum 



4. Cells of the branchlets commonly more than two diameters long, 

 the end cells aculeate C. ecuadoreanum 



Gallithatnnion soccoriense n. sp.^^^ 

 Plate 86, Fig. 2 

 Plants to 6-7 cm tall, the branching loosely spreading, the chief axes 

 percurrent, alternately branched, uncorticated, 90-140 jx diam., the cells 

 360-540 fx long; ultimate branching complanate, the penultimate branches 

 often naked for nearly the lower half of their length, bilaterally branched 

 above, the ultimate branchlets 8-15 cells long, 40-55 /jl diam., the cells 

 2-3 diameters long, slightly inflated, the branch tips somewhat sharply 

 tapered, the last 2-4 cells being much smaller than those below, but the 

 apex not acute ; tetrasporangia sessile, single near the base of the branch- 

 let on the upper side, or occasionally a second on the next higher cell, obo- 

 void, about 48 fi diam., 55 fi long, sometimes on the penultimate branch; 

 spermatangia not seen; cystocarps near the tips of minor branches, com- 

 monly singly lobed, about 120 /a diam. 



Mexico: Is. Revilla Gigedo, epiphytic on larger algae as dredged 

 from 24-32 meters at sta. 129 off Braithwaite Bay, I. Soccoro, no. 34-19 

 (tetrasporic and cystocarpic, TYPE), 3 Jan. 1934. 



Gallithamnion pacificum n. sp.^^^ 

 Plants delicate, flaccid, bushy, to 3 cm tall; main axes percurrent 

 with few main branches, below to 140-220 {x diam., the cells about as long 



158 Gallithamnion soccoriense n. sp. — Plantae ad 6-7 cm altitudine, laxe 

 ramosae, axibus primariis percurrentibus, alterne ramosis, ecorticatis, 90-140 ii 

 diam., cellulis 360-540 \x long.; ramificatione ultima complanata, ramulis 40-55 

 (A diam., cellulis 2-3 plo longioribus quam latis; tetrasporangiis sessilibus, singulis 

 prope basim ramuli in latere superiore, 48 |li diam., 55 fi long. Plantae typicae in 

 loco dicto I. Soccoro, Is. Revilla Gigedo, Mexico, legit W. R. Taylor no. 34-19, 3 

 Jan. 1934. 



159 CalHtharanion pacificum n. sp. — Plantae delicatae, fruticosae, ad 3 cm alti- 

 tudine, axibus primariis ecorticatis, percurrentibus, infra ad 149-220 \i diam., 

 cellulis 90 \i diam., 4 plo longioribus quam latis, ramulis sursum curvatis, attenu- 

 atis, irregulariter aut bilaterallter pinnatis, 0.5-1.0 mm long., ad basim 65 fx diam., 

 cellulis circa 1.5 plo diam. longitudine. Planta typica in loco dicto I. Soccoro, 

 Mexico, legit W. R. Taylor no. 39-66B, 18 Mar. 1939. 



